Organic light emitting devices (OLEDs), which make use of thin films that emit light when excited by electric current, are becoming an increasingly popular technology for applications such as flat panel displays. Popular OLED configurations include double heterostructure, single heterostructure, and single layer, as described in PCT Application WO 96/19792, which is incorporated herein by reference.
To form an array of OLEDs, the constituent materials must be patterned. Such patterning may be achieved by photoresist methods, as disclosed by U.S. Pat. No. 5,641,611 to Shieh, and in U.S. patent application Ser. No. 08/977,205 now U.S. Pat. No. 6,013,538. Shadow masks may also be used to pattern, as disclosed by co-pending U.S. patent application Ser. No. 09/182,636. Shadow masks must be thick enough to provide mechanical strength and thus, the obtainable resolution of the pattern is limited. Other methods of patterning have been used, such as excimer laser ablation and conformal masks.
While these known patterning methods are acceptable in certain circumstances, a more accurate, faster and less expensive method of patterning is desirable.